<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <script src="https://cdn.bootcss.com/vue/2.6.10/vue.js"></script>
</head>
<body>
    <div id="app">
        {{total}}
    </div>
    <script>
       var vm=new Vue({
           el:"#app",
           data(){
               return{
                   firstName:"zhang",
                   lastName:"san"
               }
           },
           /* 当参与计算的值发生改变时，总值会改变 */
           computed: {
               total(){
                   return this.firstName+this.lastName
               }
           },
       })
    </script>
</body>
</html>